Alternators generally take mechanical power (e.g., as may be supplied by an internal combustion engine of an automotive vehicle) and covert it to electrical power to generally power the automotive vehicle's electrical system (e.g., to run lights, to charge a battery and the like) when the automotive vehicle's engine is running. Such automotive alternators may substantially comprise of a rotating permanent magnet/electromagnet known as rotor, which generally spins within a hollow interior of a stator (e.g., a stationary set of insulated wires or conductors wound in coils [e.g., stator windings] around a tube-shaped frame.) The stator/rotor combination is generally encapsulated within a housing that generally defines the outside of the automotive alternator. As the mechanical action (e.g., turning of crankshaft of the automotive engine during operation) is transmitted to a drive shaft attached to the rotor, the rotor spins within the stator. This rotor rotation generally creates or induces an electrical (e.g., alternating) current (e.g., also known as AC) within the stator windings. This AC current may then be substantially transferred to a device (e.g., a bridge rectifier) to be convert it to DC (i.e. Direct Current) current for use in powering the vehicle's electrical system and alike.
The alternator housing for the rotor/stator combination could comprise of hollow housing, namely a cylindrical casing generally sandwiched between (e.g., substantially enclosed by) a drive end covering and a rectifier end covering. The rectifier end cover may further feature a rotor end bearing, bridge rectifier, and alike. Generally, a non-drive shaft end of the rotor is movably seated in the rotor end bearing of the rectifier end cover but the rotor itself does not pass out through rectifier end cover. The bridge rectifier (or alike) may be seated proximate to the rectifier end covering and be electrically connected to the stator windings to receive the AC current that the alternator creates. The bridge rectifier may additionally be electrically connected to the vehicle's electrical system to send the converted (to DC) current to power the vehicle's electrical system.
The drive end cover may support of one or more rotor shaft bearings, an oil seal, and the like wherein a portion of the rotor's drive shaft substantially passes through the drive end cover (and the respective rotor shaft bearing[s] and oil seal.) That portion of the rotor's drive shaft is generally connected to the automotive vehicle's engine, allowing the engine to mechanically power the alternator.
In heavy-duty automotive alternator applications, the resulting current generation may also result in a high heat output. To deal with this issue, the housing interiors are generally sealed off from the outside environment to allow oil from the engine to circulate through the alternators and dissipate the generated heat.
One such heavy-duty automotive alternator could be the Delco Remy 50DN oil-cooled, heavy-duty automotive alternator as manufactured, and remanufactured, by Remy International, Inc, 600 Corporation Drive, Pendleton, Ind., USA46064 for widespread use in commercial automotive applications such passenger buses and other heavy-duty, wheeled transport vehicles. This alternator's drive end cover can be seen as generally having a circular plate body defining an exterior side and an interior side, the interior side acting in concert with the housing as otherwise sealed by the rectifier end cover to generally encapsulate the stator and rotor within an oil-containing interior environment. The drive end cover's exterior side may present a mounting means or like to locate the alternator proximate to its respective powering engine. In the middle of the drive end cover and further connecting interior side with the exterior side may be a central aperture through which a portion of the rotor's drive shaft passes to the outside of the alternator. Seated inside this central aperture may be a recess that is generally located proximate to the drive end cover's interior side, the recess may further contain a ring bearing. A portion of the rotor's drive shaft passes through this bearing and spins within the bearing during alternator operation. Proximate to the drive end cover's outer side and within the central aperture may be a seated a ring-shaped oil seal. Generally seated between the rotor's drive shaft and oil seal's inner passage may be a tubular-shaped spacing collar. The spacing collar may slide over and marry the outer portion of the rotor's drive shaft with the oil seal. In this manner, an external surface of the spacing collar can be seen as presenting a generally continuous surface from the outer portion of the rotor's drive shaft passing through the oil seal that is in continuous movable contact against the mating flange of the oil seal. The oil seal's mating flange being further constructed to generally exert pressure against the external surface of the surface collar. During operation, the oil seal stays stationary with respect to drive end cover while oil's seal's mating flange substantially presses against the external surface of the spacing collar as the spacing collar/rotor drive shaft generally rotates together within the oil seal, the oil seal's purpose being the prevention of the leakage of oil from the alternator's interior to its exterior.
One possible issue with the Delco Remy 50DN Oil-Cooled, Heavy-Duty Automotive Alternator, starting from its market introduction nearly forty years ago, could be oil leakage occurring from its oil seal. This oil leakage can be significant enough in certain cases that oil could leak out onto exterior and onto rotating engine linkage/rotor drive shaft. The motion of exterior drive shaft/linkage combination could then spray the leaked oil all over the engine compartment. While such spillage could be seen as being a nuisance in attracting dirt and grime, and its presence could further increase the potential, and seriousness, of fire in the engine compartment as well.
It is believed that this leakage may be a result of construction or design flaw in the mating surface of the OEM oil seal that prevents the mating flange from adequately returning the oil riding upon the spacing collar back towards the oil-containing interior of the alternator.
Another possible oil leakage condition could be when the OEM (“Original Equipment Manufacturer) oil seal is not properly aligned when the oil seal is being fitted within the drive end cover. This lack of proper alignment could subsequently cause an improper mating of the mating flange of the oil seal and the respective outer surface of the space collar with resulting premature wear of the mating flange causing oil leakage. This improper mating could also cause a gap to occur between the oil seal and its seat in the drive end cover that allow oil leakage to occur from between the oil seal and its respective seat. Improper mating could also result if that the OEM oil seal has worn out or otherwise has subsequently failed to prevent oil from leaking out of the alternator.
As shown in FIGS. 1 and 2, the OEM (Original Equipment Manufacturer) oil seal (e.g., prior art) 200 used to seal the drive shaft of the Delco Remy 50DN oil-cooled, heavy-duty automotive alternator 100 comprises substantially of a top collar, a bottom collar, and an annular polymer sealing member. The top collar generally comprises of a top wall flange has an inwardly disposed top rim along outside edge of the top collar. This connection substantially places the top rim in a generally perpendicular orientation to the top wall flange. The bottom collar may comprise of a bottom wall flange that generally connects to a bottom ring to substantially form a mutual edge running continuously along an outside edge of the bottom ring. This connection substantially places the bottom ring in a generally angular orientation to the bottom wall flange. The bottom collar may be nested into the top collar wherein an outer side of the bottom collar is placed against an inner side of the top wall flange while the top rim and bottom ring are generally held apart from one another. The lower edge of the top wall flange may be knurled slightly inward to generally retain the bottom flange wall holding the two collars together.
The annular polymer sealing member may attach to an interior edge of the top rim to generally denote the inner passage or channel of the OEM oil seal 200. This annular polymer sealing member may further be comprised of concentric accordion-style folds to generally allow flexible adjustment in the size of the circumference of the mating flange of the annular polymer sealing member as it contacts the spacing collar. A coiled spring placed into a spring groove on a non-mating (e.g., the back side) surface of the mating flange generally moves or otherwise bias the mating flange towards a secure, yet movable contact with the spacing collar.
The mating surface may further project a radial raised ridge that may be proximate to the bottom of the mating surface. A top edge of the radial raised ridge may denote a side of a radial channel upon the mating surface, the other side of the radial channel being demarcated by an inwardly canted radial projection or flange (that may also further contact the spacing collar) at the top of the sealing member.
The radial raised ridge may further present a set of angularly-oriented, spaced apart, non-parallel splines. It is believed that originally the driveshaft of the Delco Remy 50DN oil-cooled, heavy-duty alternator in at least one application rotated clockwise and for another automotive application, the driveshaft rotated counterclockwise. To accommodate these two opposing rotational movements, the OEM oil seal splines 76 are organized in a wave format with the splines 76 being alternatively disposed in left hand (counterclockwise) and right hand (clockwise) orientations. The splines 76 in alternating or wave-like orientation generally created a corresponding set of triangle-shaped return grooves 78. When the splines 76 contacted the oil brought by the spacing collar 104, the splines 76 were to generally direct the oil into the return grooves 78. The return grooves 78 were then generally expected to move oil back to the oil-filled alternator interior. This resulting dual application (e.g., alternating or wave-like spline 76 orientation/triangular-shaped return groove 78 orientation was found to be a less than effective means of redirecting oil from the spacing collar 104 back towards the oil-filled alternative interior and thus possibly contributing to the oil leakage issues occurring with Delco Remy 50DN oil-cooled, heavy-duty automotive alternators.
What may be needed therefore is new oil seal for drive end cover of Delco Remy 50DN Oil Cooled, Heavy Duty Automotive Alternator. Such a new seal could have an improved mating flange whose spline-based surface could cause oil moving between the spacing collar, splines, and return grooves to be more effectively returned to the oil-containing interior of the Delco Remy 50DN alternator housing. The new oil seal could be made structurally stronger top collar to resist warping that may occur when the new oil seal is seated within the drive end cover. The new oil seal could further have the annular polymer sealing member covering the outer side/bottom edge of the top wall flange of the top collar to generally increase the sealing capability of new oil seal to the drive end cover.